/*
 * Copyright (C) 2013, 2016 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include "include/JavaScriptCore/heap/DeferGC.h"
#include <wtf/Lock.h>
#include <wtf/NoLock.h>
#include <wtf/Optional.h>

namespace JSC {

#if ENABLE(CONCURRENT_JS)
    typedef Lock ConcurrentJSLock;
    typedef LockHolder ConcurrentJSLockerImpl;
#else
    typedef NoLock ConcurrentJSLock;
    typedef NoLockLocker ConcurrentJSLockerImpl;
#endif

    class ConcurrentJSLockerBase : public AbstractLocker {
    WTF_MAKE_NONCOPYABLE(ConcurrentJSLockerBase);
    public:
        explicit ConcurrentJSLockerBase(ConcurrentJSLock &lockable)
                : m_locker(&lockable) {
        }

        explicit ConcurrentJSLockerBase(ConcurrentJSLock *lockable)
                : m_locker(lockable) {
        }

        explicit ConcurrentJSLockerBase(NoLockingNecessaryTag)
                : m_locker(NoLockingNecessary) {
        }

        ~ConcurrentJSLockerBase() {
        }

        void unlockEarly() {
            m_locker.unlockEarly();
        }

    private:
        ConcurrentJSLockerImpl m_locker;
    };

    class GCSafeConcurrentJSLocker : public ConcurrentJSLockerBase {
    public:
        GCSafeConcurrentJSLocker(ConcurrentJSLock &lockable, Heap &heap)
                : ConcurrentJSLockerBase(lockable), m_deferGC(heap) {
        }

        GCSafeConcurrentJSLocker(ConcurrentJSLock *lockable, Heap &heap)
                : ConcurrentJSLockerBase(lockable), m_deferGC(heap) {
        }

        ~GCSafeConcurrentJSLocker() {
            // We have to unlock early due to the destruction order of base
            // vs. derived classes. If we didn't, then we would destroy the
            // DeferGC object before unlocking the lock which could cause a GC
            // and resulting deadlock.
            unlockEarly();
        }

    private:
        DeferGC m_deferGC;
    };

    class ConcurrentJSLocker : public ConcurrentJSLockerBase {
    public:
        ConcurrentJSLocker(ConcurrentJSLock &lockable)
                : ConcurrentJSLockerBase(lockable)
#if ENABLE(CONCURRENT_JS) && !defined(NDEBUG)
        , m_disallowGC(std::in_place)
#endif
        {
        }

        ConcurrentJSLocker(ConcurrentJSLock *lockable)
                : ConcurrentJSLockerBase(lockable)
#if ENABLE(CONCURRENT_JS) && !defined(NDEBUG)
        , m_disallowGC(std::in_place)
#endif
        {
        }

        ConcurrentJSLocker(NoLockingNecessaryTag)
                : ConcurrentJSLockerBase(NoLockingNecessary)
#if ENABLE(CONCURRENT_JS) && !defined(NDEBUG)
        , m_disallowGC(std::nullopt)
#endif
        {
        }

        ConcurrentJSLocker(int) = delete;

#if ENABLE(CONCURRENT_JS) && !defined(NDEBUG)
        private:
            std::optional<DisallowGC> m_disallowGC;
#endif
    };

} // namespace JSC
